When people find out I am a DUI Attorney here in Las Vegas, the first question they ask is how to beat the Field Sobriety tests and Breathalyzer. You know how you beat those tests? Call a cab. Don't drink and drive. There is no secret trick to beating any of those things. Even the field sobriety tests aren't what you think they are.
The National Highway Traffic Safety Administration (NHTSA) came up with three nationally approved field tests for police officers to administer:
(1) The Walk and Turn;
(2) Pen/Light test;
(3) Stand on one foot.
Now tests 1 and 3 are designed to see if you can follow directions, not really to test your balance (of course if you are stumbling drunk then it is pretty obvious). Everyone's balance is different. The real key is to listen to what the officer is saying and follow his directions very closely. Pretend like it is a game of Simon Says, and do not move unless he tells you to...
Test two is something you can't really "beat". They are checking your vision to see if you are driving under the influence, and if you have been, then they will be able to tell using this pen/light test.
At the end of the day, always be polite to the officer and follow his directions. Also, always call a cab. But, if you don't and need some assistance, make sure you contact a criminal defense attorney to help you!